Radiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography

doi:10.1016/j.nuclcard.2007.09.028

Journal of Nuclear Cardiology

Volume 15, Issue 2, March–April 2008, Pages 232-240

This study was presented in part at the American College of Cardiology 55th Annual Scientific Session, Atlanta, Ga, March 13, 2006.

https://doi.org/10.1016/j.nuclcard.2007.09.028 Get rights and content

Background

Recent advances have led to a rapid increase in the number of computed tomography coronary angiography (CTCA) studies performed. Whereas several studies have reported the effective dose, there are no data available on cancer risk for current CTCA protocols.

Methods and Results

Effective and organ doses were estimated, by use of scanner-derived parameters and Monte Carlo methods, for 50 patients having 16-slice CTCA performed for clinical indications. Lifetime attributable risks were estimated with models developed in the National Academies’ Biological Effects of Ionizing Radiation VII report. The effective dose of a complete CTCA averaged 9.5 mSv, whereas that of a complete study, including calcium scoring when indicated, averaged 11.7 mSv. Calcium scoring increased effective dose by 25%, whereas tube current modulation reduced it by 34% and was more effective at lower heart rates. Organ doses to the lungs and female breast were highest. The lifetime attributable risk of cancer incidence from CTCA averaged approximately 1 in 1,600 but varied widely among patients, being highest in younger women. For all patients, the greatest risk was from lung cancer.

Conclusions

CTCA is associated with non-negligible risk of malignancy. Doses can be reduced by careful attention to scanning protocol.

Section snippets

Patients

Fifty consecutive patients having CTCA performed at the Mount Sinai Hospital (New York, NY) for whom scan data were available were considered for the analysis. The study was approved by the Mount Sinai Institutional Review Board.

CT Scan Protocol

All examinations were performed on a 16-slice multidetector-row CT scanner (Somatom Sensation 16 equipped with VB10 software; Siemens AG, Munich, Germany) with spiral technique. Intravenous β-blockers were given to lower patients’ heart rates to a target rate of less

Patients

CTCAs were evaluated from 50 patients (30 men and 20 women). The mean age was 61 ± 12 years (range, 34 to 82 years). Nine patients who had undergone coronary artery bypass surgery, as well as two additional patients, had a scan including the heart, ascending aorta, and aortic arch. The low–heart rate protocol was used in 2 patients. The mean heart rate during CTCA, after β-blockade, was 62.9 ± 8.6 beats/min (range, 49 to 88 beats/min).

Scan Parameters

The average maximum effective mAs for CTCA was 500 ± 37 mAs

Discussion

The main findings in this study are as follows: (1) the mean effective dose for a complete CTCA scan was 9.2 mSv in men and 10.1 mSv in women, whereas the inclusion of calcium scoring increased this value by 25% to 11.0 and 12.7 mSv, respectively; (2) weighted equivalent doses were highest to the lungs (4.2 mSv) and female breast (1.9 mSv); (3) the risk of cancer developing from CTCA averaged 1 in 1,600 and the risk of fatal cancer developing averaged 1 in 1,900; and (4) the primary contributor

Acknowledgment

Dr Einstein has served as a consultant to GE Healthcare (Waukesha, WI) and received travel funding from Philips Medical Systems (Andover, MA). Dr Henzlova has given lectures for Bristol-Myers Squibb (North Billerica, MA) and received research grants from GE Healthcare, Molecular Insight Pharmaceuticals (Cambridge, MA), and Cardiovascular Therapeutics (Palo Alto, CA).

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: This work was supported in part by a National Institutes of Health/National Center for Research Resources Clinical and Translational Science Award (1 UL1 RR-24156-01).

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Original articleRadiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography

Background

Methods and Results

Conclusions

Section snippets

Patients

CT Scan Protocol

Patients

Scan Parameters

Discussion

Acknowledgment

J Am Coll Cardiol

Semin Ultrasound CT MR

J Am Coll Cardiol

J Am Coll Cardiol

Lancet

High-resolution spiral computed tomography coronary angiography in patients referred for diagnostic conventional coronary angiography

Circulation

Managing patient dose in computed tomographyA report of the International Commission on Radiological Protection

Ann ICRP

Radiation dose to patients from cardiac diagnostic imaging

Circulation

Radiation dose estimates from cardiac multislice computed tomography in daily practice: impact of different scanning protocols on effective dose estimates

Circulation

Radiation exposure during cardiac CT: effective doses at multi-detector row CT and electron-beam CT

Radiology

Estimation of radiation exposure in 16-detector row computed tomography of the heart with retrospective ECG-gating

Rofo

The importance of end-systole for optimal reconstruction protocol of coronary angiography with 16-slice multidetector computed tomography

Invest Radiol

Radiation dose in computed tomography of the heart

Circulation

European guidelines for multislice computed tomography

Original article
Radiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography